I have a MKV video file that my hard disk can only read the audio but not the video but it works fine on my computer. Any chance I need to update the codec on my device?

Well, you can’t update codecs, so lets hope that’s NOT the case.

Please post the full TEXT output of MEDIAINFO for such a file.

here u go…

It has header stripping. You’ll need to remix using MKVMerge 4.0.0 or earlier.

Can you please explain a little bit?

I have the program but all I can do with it, is to extract the video or audio

Look into this post: